Natural forms can be some of the hardest to re-create in a 3D model, and that’s where a procedurally based modeling application can come in handy. A procedural modeler generates the parts of the model by following mathematical functions whose initial conditions are set by the user. Some procedural modelers, such as Xfrog or the Tree Modeler in Carrara, specialize in generating models of various plants using mathematical formulas which have been derived from observation of actual plants and the way that they grow. Another type of procedural modeler can be used for the generation of spiral shaped objects like seashells. Two programs of this type that have been available for a while are Spiralizer and ShellyLib, and they are the topic of this article.

The Spiralizer program from Armanisoft is an early modeler of this type. It is available for Windows XP/2000/NT 4.0/95/98 (no Macs), and it is freeware with donations acceptable via PayPal. Spiralizer is easy to use, with an intuitive interface. When you like the look of your model, you can export it in the DXF or POVRay formats.

ShellyLib is a more advanced procedural modeler, specifically designed to generate seashell-like objects. It is listed as available for Windows NT/95/98 as well as for Linux and Irix. I have had no problems running it on machines with Windows 2000 or Windows XP.
ShellyLib is shareware, available for $20 USD through ShareIt. A save-disabled demo is also available for download. ShellyLib comes with a preset library of different seashell types. The models from ShellyLib may be exported in several formats including DXF, POVRay, and TrueSpace (COB).

The models I have built with Spiralizer and ShellyLib were exported in the DXF format, and then converted to the OBJ format using Crossraods3D or the Amapi modeler. The OBJ files were imported into UnWrap3D for UV mapping. The UV mapped models were then imported into Carrara for rendering.

Spiralizer

A screenshot of the Spiralizer interface is shown below. The model is shown in wireframe mode, and it is ready to be exported for further work.

The image below shows the model after being imported in the Amapi modeler.

Extrusion was applied to the faces of the model to add some detail as shown below:

The model was exported from Amapi in the Wavefront .OBJ format. It was then imported into UnWrap3D for UV mapping. The model was sliced into sections which were overlaid on the UV mapping area since having the texture repeat at smaller sizes down the length of the shell would not be a problem. A checkerboard pattern was applied to see how the final texture would be fitted to the model.

The UV mapped model was then imported into Carrara. A procedural shader was applied to produce the render shown below.

ShellyLib

As can be seen in the screenshot below, ShellyLib has a lot more functionality than Spiralizer. The library of preset models is a big help in getting started. In addition to the tried-but-true method of learning by tweaking, there is also documentation covering the program and its controls.
Click on the image to see a larger version.

The ShellyLib models shown here were exported in the DXF format and converted to Wavefront OBJ format by passing them through the Crossroads3D program. The models were UV mapped in UnWrap3D, then imported into Carrara for texturing and rendering.

Here is the Cerith preset….

…the Lyria preset….

…and the Threenod preset.

Wrapping Things Up

Spiralizer and ShellyLib have been on the scene for a while, filling a rather specialized niche in the world of 3D programs. If you’re interested in seashells, want to make models for use in 3d renders of marine scenes, or simply want to try something different, then these programs are worth checking out.